How to totally get rid of Clover??

Hi and help!!

I have just upgraded my pc and decided it was time to switch over from Clover to OC and have a crack at installing Big Sur beta. Success with the install but when I went to copy over the OC folder to my EFI, I noticed that the old Clover folder was there. I deleted it but upon reboot, I was presented with clover still and no OC. Any help would be appreciated as I don't know what to do from here and I'd rather not reinstall again.

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Thanks!